The expression of endogenous type C RNA-viral genes in mammalian tissues is being investigated. Current studies include: 1) the expression of viral genes during embryonic development; 2) the mechanism of induction of viral genes by estrogen hormones in the NIH Swiss mouse uterus; 3) the association between endocrine imbalance and oncornaviral genes in the pathogenesis of adrenal carcinoma in ovariectomized mice. BIBLIOGRAPHIC REFERENCE: Strickland, J. E., Saviolakis, G. A., Folwer, A. K., Kouttab, N. M., and Hellman, A.: Impaired-estrogen mediated production of type C viral DNA polymerase in aged NIH Swiss mouse uteri. Proc. Soc. Exp. Biol. Med. 153: 63-69, 1976.